Heart

Question 1

Name the 4 chambers of the heart

Answer 1

Left and right atrium

Left and right venricle

Question 2

Name the 2 veins that bring blood into the atria

Answer 2

Vena Cava

Pulmonary vein

Question 3

Name the 2 arteries that carry blood away from the ventricles

Answer 3

Aorta

Pulmonary artery

Question 4

Name the valves found in the heart

Answer 4

Atrioventricular valves

Question 5

What is the function of the atrioventricular valves?

Answer 5

Prevent the back flow of blood into the atria when the ventricle walls contract.

Question 6

Explain why the atria walls are thinner than the ventricle walls.

Answer 6

Blood does not need to be pushed under high pressure so walls do not need to contain large amounts of muscular tissue

Question 7

Describe what happens during atrial systole

Answer 7

Atria contract.
Blood pressure in the atria increases
Atrioventricular valves open
Blood is pushed into the ventricles.

Question 8

Describe what happens during ventricular systole

Answer 8

Ventricles contract. 
Blood pressure in the ventricles increases
Atrioventricular valves close 
Semi lunar valves open
Blood flows into the arteries.

Question 9

The heart tissue is myogenic. What does this mean?

Answer 9

The contraction of the heart is initiated from within the muscle rather than by nerve impulses.

Question 10

Explain how the contraction of the heart is controlled.

Answer 10

SAN generates a wave of electrical excitement that cross the atria, causing the muscle to contract
AVN receives, delays and then passes an electrical impulse down the bundle of His to the apex of the heart.
Impulse travels into the Purkinje fibres which branch across the ventricles causing them to contract form the apex upwards

Question 11

Why does the AVN delay the impulse along the bundle of His?

Answer 11

Allow time for the blood to pass through the atrioventricular valve and into the ventricles